Dications of 3-Phenylindenylidenefluorenes: Evaluation of Antiaromaticity of Indenyl and Fluorenyl Cations by Magnetic Measures
作者:Nancy S. Mills、Kathleen B. Llagostera、Cornelia Tirla、Stacey M. Gordon、Donald Carpenetti
DOI:10.1021/jo060346d
日期:2006.10.1
antiaromaticity of indenyl monocations compared to fluorenyl monocations. The presence of a phenyl substituent in the 3-position was able to stabilize the indenylidene cation through resonance, decreasing its antiaromaticity, but even in the absence of the 3-phenyl substituent, the indenyl system of indenylidenefluorene dications was less antiaromatic than the fluorenyl system. The decreased antiaromaticity of
制备对位取代的3-苯基茚基亚芴的阳离子,以检查所得的茚基和芴基阳离子体系对抗芳构性的磁性测量的响应。的所有措施,1角1 H NMR位移,核独立化学位移(NICS(1)ZZ),和磁化率提高,Λ,所支持的双阳离子的反芳香性3A - ˚F 2+。的1角1 H NMR位移和NICS(1)ZZ结果表明,茚基环体系的抗芳香性低于芴基环体系,这与茚基单阳离子与芴基单阳离子的抗芳香性相反。在3-位上存在苯基取代基能够通过共振稳定茚基阳离子,从而降低其抗芳香性,但是即使在不存在3-苯基取代基的情况下,茚基亚芴基阳离子的茚基系统也比芴基系统的芳香性低。 。(反)芳族(去)稳定能计算,ASE支持了3-苯基茚基芴指示剂相对于未取代的茚基芴指示剂降低的抗芳香性。